The present invention is directed to bicycles and, more particularly, to various features of a method and apparatus for controlling a bicycle transmission.
Bicycle transmissions that are operated by an electric motor or the like have recently become known. Such transmissions may be shifted automatically according to the bicycle speed shifted manually by the rider. Typically, a shift command is generated according to the bicycle speed or manual input by the rider, the motor is controlled by a transmission operating unit in response to the shift command, and the speed step of the transmission is set accordingly.
Shift commands sometimes are generated while the transmission is being operated. When prior art systems receive shift commands at this time, either the shift commands are ignored, or else the shift commands are saved and executed sequentially when the transmission operation is complete. If shift commands are ignored in the case of manual shifting, then the rider""s intentions are not carried out. Furthermore, in such a system the rider must personally keep track of when shifting operations begin and end, which is very undesirable for a supposedly automated system. On the other hand, when the shift commands are saved and executed sequentially when the transmission operation is complete, there is a risk of wasted effort. More specifically, sometimes the rider enters a series of upshift and downshift commands, either because of changing conditions or because of initial misjudgment of the desired gear. If, for example, the rider wanted to enter a single upshift command but mistakenly entered two upshift commands and then entered a downshift command to correct the error, then in prior art systems the transmission would make a total of three shifts instead of one. Such a mode of operation creates unnecessary wear on the components, it requires more time to execute all of the shift commands, and it unnecessarily drains the power supply.
The present invention is directed to various features of a method and apparatus for controlling a bicycle transmission. In one embodiment of the present invention, a shift command receiving unit is provided that receives shift command signals corresponding to shift commands, and a shift command combining unit is provided that combines a plurality of the shift command signals into a resultant shift command signal that would shift the bicycle transmission to the same state as if the plurality of shift commands all were executed individually. A method according to the present invention includes the steps of receiving shift command signals corresponding to shift commands, and combining a plurality of the shift command signals into a resultant shift command signal that would shift the bicycle transmission to the same state as if the plurality of shift commands all were executed individually. Additional inventive features will become apparent from the description below, and such features may be combined with the above features to provide additional benefits.